Electric heater for oil-wells.



J. WLI..IAIvSUN.

ELECTRIC HEATER POR OIL WELLS.

APPLICATION FILED 00T. 2B, 190B.

Patented 001;. 11, 1910.

lill.,IllillilllIlllilillllllillll UNITED STATES PATENT OFFICE.

JAMES E. WILLIAMSON, OF PITTSBURG, PENNSYLVANIA.

ELECTRIC HEATER FOR OIL-WELLS.

To all whom it may concern:

Be it known that I, JAMES E. WILLIAM- soN, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electric Heaters for Oil-Wells, of which improvement the following is a specification.

My invention relates to improvements in electric heaters for oil wells.

The present invention is an improvement upon a certain heater described and claimed in Letters Patent of the United States No. 806,03, dated November' 28th, 1905, and is intended to remedy a serious defect in said patented heater. The heater described-in said Patent,-No. 806,039, comprised an electric resistance so disposed upon the pump tubino' that said resistance could be positioned thereon without removing the tubing and without stopping the pumping operation. There was not, however, shown any mea-ns to prevent harmful results, occasioned by the expansion and contraction of the parts of said heater subjected to varying temperatures, particularly the outer or inclosing tube or tubing, the result being that water or moisture was liable to enter at the joints and interfere with the eiliciency of the heater.

The object of the present invention is to provide means to avoid or prevent the harmful effects of the expansion and contraction in the heater, and, at the same time, to utilize the inner tube as a terminal or conductor for the return circuit. I accomplish these objects by means of the device hereinafter described, reference being had to the accompanying drawings, forming part hereof, in which- Figure 1 is a vertical section of my improved heater; Fig. 2 is the same, showing a modified form of means to close the ends of the heater; Fig. 3 is a vertical central Specification of Letters Patent.

Application filed October 26, 1908.

Patented Oct. 11, 1910.

Serial No. 459,455.

and an orifice b through which the terminal 3 of the electric resistance t passes, and is welded to the inner lower end of the shell 5, which is suitably secured to the upper end of the shell l., as hereinafter described. The plug G is screwed into the lower end of the shell 5, and the gasket 7 of rubber or other suitable material is interposed between said plugs 2 and G; the said plug 6 and gasket T are each provided with an orifice Z and e to permit the terminal to pass therethrough. Thel closure at the lower end of said shell comprises the plug S, which is welded to the inner lower end thereof, and is provided with a centrally disposed orifice f, through which the inner tube 9 projects, and with a socket g. The said socket g is for the reception of a gasket it, the lower end of which is engaged by the nut 10, which is screw threaded and operates upon the lower end of the correspondingly threaded inner tube 9, and serves to draw the lower edge of the shell 5 tightly against the gasket z' which is interposed between the upper edge of shell 1 and the lower edge of said shell 5. The said plug or closure 8 is welded to the inner lower end of the shell l below the corrugations 11, which are formed in the wall of said shell, the function of said corrugations being to take up the expansion and contraction within the device and thus conserve and prevent harmful effects from expansion and contraction in said shell 1 and in the tube 9 occasioned by the heat generated by the resistance et, one terminal 3 of which enters through the closure in the upper end of the shell 1 and is wound around the inner tube 9, the outer surface of which is provided with suitable insulation 12, the other terminal of said resistance being grounded or brought into contact with said tube at .'20, whereby the current is returned through said tube. The ends 7L and e" of said inner tube 9 project out of the inclosing shell 1, and are screw threaded to enable the ordinary pump tube m to be connected therewith at the upper end, and an anchor n at the lower end, as shown in Fig. 3. It is Obvious, however, that the inner tube 9 may be made large enough to slide over and upon the pump tube and that the return circuit may be carried through said tube.

The structure shown in Fig. 2 is a modied form of closures, which water seal the upper and lower ends respectively of the device. The upper closure comprises a plug 14, which is welded to the lower inner end of the shell 15, and to the inner tube 16, a screw threaded plug 17 and a gasket 18 interposed between said plugs. The said plugs 141- and 17 and gasket 18 are provided each with a centrally disposed oriiice through which the inner tube 16 is inserted, the end of said tube being reduced for such purpose, also with oriiices through which the upper terminal of the resistance 19 passes, the said resistance being wound around the inner tube 16, which is provided with suitable insulation on the exterior thereof, and is grounded or brought into contact with said tube 1G, whereby the current is returned through said inner tube. The lower end of the outer shell 19 is closed water tight by a closure which comprises a plug 20, which is inserted in the inner lower end of the shell 19, a plug 21 which is screw threaded and secured in the lower inner end of the shell 19 and provided with screw threaded oriiices 7' and lc in which screw threaded bolts 22 are secured. Gaskets 23 and 24 are interposed between said plug 20 and plug 21 constituting a stuiiing boX, the said bolts being inserted in the screw threaded orifices in the plug 20 for the purpose of bringing the plug 21 tightly against the gaskets interposed between said plugs, at such times as the nut 24, which operates upon the screw threaded end of the inner tubing, is tightened or operated, and when expansion occurs in said tubes, the purpose of this modied construction being to transfer the edect of the eX- pansion and contraction to the various gaskets interposed at the joints.

It is obvious that other forms of expansion joints may be used than the two forms shown and described without departing from the invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. In an electric heater for oil wells, the combination with the pumping tube, of a heater comprising an outer and an inner shell, and an electric resistance arranged upon the exterior of the inner shell, the said shell constituting the return conductor of said resistance, the said resistance being located in a water sealed chamber between said shells, the inner shell being adapted to be connected to said pumping tube, and the outer shell having a series of corrugations in the wall thereof.

2. In an electric heater for oil wells, the

combination with the pumpingmtubepf a v.

heater comprising an outer and an 1nner shell, the outer shell having a series of corrugations in the wall thereof, the inner shell having an extension at one end adapted to be connected to the pumping tube and a resistance wound around the exterior of said inner shell, the said shell constituting the return conductor of said resistance.

3. An electric heater for oil wells comprising an outer and an inner shell, the inner shell being open at both ends and adapted to be connected to the pump tubing, the ends of the outer shell being water sealed around said inner shell, and expansion joints for taking up the expansion and contraction within said heater, and an electric resistance wound around said inner shell, the said shell constituting the return conductor of said resistance.

In testimony whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

JAMES E. WILLIAMSON.

, In the presence of- CLARENCE A. WILLIAMS, JOHN H. RONEY. 

